Conformationally restricted, spatially defined 12-30 membered macrocyclic ring systems of type (I) are constituted by three distinct building blocks: an aromatic template a, a conformation modulator b and a spacer moiety c as detailed in the description and the claims. Macrocycles of type (I) are readily manufactured by parallel synthesis or combinatorial chemistry. They are designed to interact with specific biological targets. In particular, they show agonistic or antagonistic activity on the motilin receptor (MR receptor), on the serotonin receptor of subtype 5-HT2B (5-HT2B receptor), and on the prostaglandin F2•receptor (FP receptor). They are thus potentially useful for the treatment of hypomotility disorders of the gastrointestinal tract such as diabetic gastroparesis and constipation type irritable bowl syndrome; of CNS related diseases like migraine, schizophrenia, psychosis or depression; of ocular hypertension such as associated with glaucoma and preterm labour.